MICHIGAN CITY, Ind. — Mount Baldy is still moving, but its movement has been slowed.

Mount Baldy features high hills of wild, wind-swept sand, topped by grasses, shrubs and small trees. It rises 126 feet above Lake Michigan and is one of the biggest attractions at Indiana Dunes National Lakeshore. It is the one dune at the federal lakeshore in northern Indiana that visitors are welcome to climb up and slide down.

Lakeshore officials have added barriers to keep visitors on designated trails atop Mount Baldy to stabilize the vegetation on the tallest moving sand dune on the lakeshore.

The dunes are shaped by northwest winds that carry the sand 4 to 5 feet inland a year. Grasses and trees are unable to stop the sand's movement when the wind exceeds 7 mph.

The National Park Service adopted what's called the Mount Baldy Dune Protection Plan in early 2011 to slow and reverse damage to the dunes from the trampling feet of visitors, which accelerated the sand movement to what the Park Service calls an alarming rate. The wind has been moving sands and slowly burying trees on the dune's southern flank.

The federal initiative is helping at Mount Baldy and may be used at other heavily visited dunes on the lakeshore, officials said.

You still climb two trails to reach the top of Mount Baldy, but parts of the dune now are off-limits. The southern slope, with its half-buried trees above the parking lot, is closed, as is a third trail. You can scale the dune from the lakeside or take a trail to the top and then hike down its north face. Its loop is about three-quarters of a mile.

Mount Baldy, a bowl-shaped dune at the eastern end of the 15,067-acre federal park, is an impressive sight. From the top, you will see a nearby power plant, steel mills to the west in Gary and, on clear days, the Chicago skyline.

The elongated lakeshore stretches 30 miles along Lake Michigan from Gary to Michigan City. Indiana Dunes, with its 15 miles of beaches and recreational and historical attractions, is a popular warm-weather playground, attracting nearly 2 million summer visitors.

The lakeshore encompasses 2,182-acre Indiana Dunes State Park and several state-run nature preserves in Porter, Lake and LaPorte counties. It is a mosaic of dunes, prairies and bogs at the edge of heavily industrial northwest Indiana

These are among the world's highest freshwater dunes, distinctive for their plant diversity. There are about 1,400 species of vascular plants in six distinctive plant communities. Strangely, you will find Arctic plants and desert vegetation thriving together.

Interestingly, Indiana Dunes is where the term "plant succession" was coined in 1899 by University of Chicago biology professor Henry Cowles.

One of the key plants is marram grass, which pokes up through the sand and thrives in the extreme conditions. The narrow waxy leaves and the dual-purpose root system help it endure high winds, shifting sands and temperatures that range from below freezing to desertlike heat. The grass spreads its roots and keeps the sand from shifting. A single marram grass may spread more than 20 feet in diameter. Its roots can also emerge as new plants.

The Park Service planted 200,000 marram grass plants in 2012 to anchor the dunes.

You will find marram grass, sand cherry, wild grapes, bluestem grass, milkweed, cottonwood trees and puccoon flames in what's called the foredunes. In the middle dunes, the plants include arctic bearberry, jack pine, white pine and common juniper. The oldest dunes are home to black oak, witch hazel and winged sumac.

Between the dunes, you are apt to find low-lying, hummocky wetlands.

Blowouts are places where winds have blown away sand and exposed long-buried trees. One of the biggest blowouts is 300 yards long and can be found at the eastern end of the state park. You can access it from the state park or from Kemil Beach.

The state park is also home to the tallest dune: Mount Toms at 192 feet.

Indiana Dunes features "singing sands," but I have not heard them, despite extensive beach walking. The combination of quartz crystals, moisture, pressure and the friction from your feet on the sand can create a clear, ringing sound that can be heard as far as 30 feet away. It may occur once a month when conditions are right, according to park officials.

Getting protection for Indiana Dunes was not easy. There was a failed effort to protect them in 1916. The state park was created in 1923 and the federal park in 1966.

Swimming is permitted at the lakeshore, but the Park Service advises caution because the Lake Michigan waters can be dangerous. High winds and waves can create rip currents, and the lake bottom is uneven and filled with holes.

Lifeguards are on duty only at West Beach. The summer fee is $6 per vehicle.

Camping is available in the lakeshore's 79-unit Dunewood Campground from April 1 to mid-October. Private campgrounds are nearby, and the state park offers camping. It has a nature center and 16.5 miles of hiking trails.

The lakeshore offers 45 miles of trails for hiking and bicycling. One of the most rugged is the Cowles Bog Trail that runs 5 miles through high dunes, wetlands and oak savannas. It is off Mineral Springs Road off U.S. 12. The bog is a National Natural Landmark.

There are three loop trails at West Beach that stretch 3.5 miles: the Dune Succession, Long Lake and West Beach trails. There is a great overlook on the Dune Succession Trail, along with 200 wooden steps that ascend the dune's face.

West Beach is the most popular area of the park. You will find fewer people and more solitude farther to the east.

You also can drive past five houses on Lakefront Drive east of the state park. They were part of the Homes of Tomorrow exhibit at the 1933 World's Fair in Chicago.

For information on the national lakeshore, call 219-926-7561 or visit nps.gov/indu. A good place to start your visit is the visitor center at 1215 N. State Route 49, Porter, Ind.

For the state park, call 219-926-1952, in.gov/dnr. The summer fee is $10 for out-of-state vehicles.